1. Field of the Invention
The present invention relates to an apparatus and method for improving reception performance of a mobile communication system. More particularly, the present invention relates to an apparatus and method for, when generating a statistic signal of a similar characteristic with that of an input signal of a receive apparatus and obtaining the optimal filter coefficient through an adaptive equalization algorithm, reducing a hardware size through a partial tap coefficient update.
2. Description of the Related Art
Mobile communication systems use a variety of demodulation techniques between a Base Station (BS) and a portable terminal to enable high-speed data transmission. For example, Time Division Multiple Access (TDMA) mobile communication systems (e.g., Global System for Mobile communication (GSM)/General Packet Radio Service (GPRS)/Enhanced Data rate for GSM Evolution (EDGE)) demodulate receive signals using Maximum Likelihood Sequence Detection (MLSD).
The MLSD provides excellent performance compared to other demodulation techniques, but has a problem that, due to its complexity, realization is difficult in a broadband communication system. Thus, if the MLSD cannot be applied, a linear equalizer or linear feedback equalizer is used.
The linear equalizer includes a linear filter to maximize a Signal to Interference Ratio (SIR) of a demodulation signal. However, despite providing excellent performance compared to a rake receiver, the linear equalizer has a problem in that a structure is more complex and power consumption is greater than the rake receiver. Thus, the rake receiver had been used for a portable terminal but, due to a limitation of high-speed data transmission, the linear equalizer providing excellent performance has been adopted and used.
The linear equalizer applies an adaptive equalization algorithm for determining the optimal filter coefficient using an existing signal without estimating a channel and a noise power. However, the adaptive equalization algorithm repeatedly performs a process for identifying an existing signal to identify the optimal filter coefficient and acquires the optimal filter coefficient. Thus, there occurs a problem of not being capable of acquiring the optimal filter coefficient in circumstances in which a channel state changes frequently.
That is, the above receive method can apply an algorithm for identifying the optimal filter coefficient in a static environment, but has a problem of, in a high-speed mobility environment in which a frequent channel change takes place, not being capable of applying an adaptive equalization algorithm for identifying the optimal filter coefficient.
As a method for solving the above problems, Korean patent application No. 10-2008-0057722 for Adaptive Equalization Algorithm using Statistic Signal Regeneration (SSR) was filed on 19 Jun. 2008 in the name of Samsung Electronics. In the above method using a statistic signal, a plurality of signals having the same characteristic as an input signal are regenerated using a measured channel estimation value and are used as an input of the adaptive algorithm.
The adaptive equalization algorithm is relatively less complex even at a high speed and provides the same excellent performance as Linear Minimum Mean Square Error (LMMSE) realization. However, there is a problem that, because obtaining a weight through the adaptive equalization algorithm is comparatively computationally intensive, the adaptive equalization algorithm has no choice but to have large-size hardware.